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<h3 class="heading"><span class="type">Paragraph</span></h3>
<p><dfn class="terminology">Solution</dfn> Consider</p>
<div class="displaymath process-math" data-contains-math-knowls="">
\begin{equation*}
({\bf A} -r{\bf I} ) \vec{\xi}={\bf 0}.
\end{equation*}
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<p class="continuation">We have</p>
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\begin{equation*}
|{\bf A} -r{\bf I} |=0 \to
\left|
\begin{array}{cc}
2-r &amp; -5\\
1 &amp; -2-r
\end{array}
\right|=0 \to 
r_1=i,\quad r_2=-i. \quad (\lambda=0, \mu=1)
\end{equation*}
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<span class="incontext"><a href="sec6_6.html#p-288" class="internal">in-context</a></span>
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